Starting device for internal combustion engines



Aug. 25, 193%. CALLSEN 2,052,127

STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed April 18, 1932 2 Sheets-Sheet 1 A. CALLSEN Aug. '25, 1936.

STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed April 18, 1932 Patented Aug. 25, 1936 PATENT OFFICE STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Albert Callsen, Stuttgart, Germany, assignor to Robert Bosch Aktiengesellschalt,

Germany Stuttgart,

Application April 18, 1932, Serial No. 606,006 In Germany April 24, 1931 13 Claims. (01. 123-179) The present invention relates to a starting device for internal combustion engines, in which an inertia mass is brought to a high speed of rotation by means of an electric motor or by hand, and then coupled to the internal combustion engine to be started, and in which a friction clutch is introduced between the pinion engaging in the rim of the flywheel of the engine and the inertia mass.

In a known arrangement the pinion is permanently connected with the inertia mass so as to transmit power through a spring-loaded plateclutch.

This construction has the disadvantage that each time on the engagement of the pinion in the toothed rim of the flywheel of the motor the pinion as well as the toothed rim of the flywheel are strongly worn and even are often damaged. It is also already known in electric starters which have no separate inertia mass to make the plateclutch inserted between the pinion and the armature of the starting motor capable of transmitting power by a pressure member which can screw axially on the driving shaft. In this case the clutch only establishes the power connection when the pinion, on coming into engagement, is prevented from freely rotating. In order however, that the pinion may fully engage, it must become engaged by an auxiliary force before the transmission of the main torque, since an immediate engagement under full load would not be possible because the flank pressure of the teeth is so great from the first moment of the engagement-that the axial attractive force of the armature does not suffice to entirely push in the pinion. This second construction is thus not at all possible for flywheel starters because in these the full torque is present immediately upon engagement.

According to the present invention thedrawback of the first-mentioned construction is removed, whilst the starting device of the secondnamed construction is also made applicable to flywheel starters in that the power connection between the pinion and the inertia mass, which is effected by a plate-clutch operated by an axial-- ly screwing pressure member, is capable of being initiated at will. i

An example of construction of a starter according to the invention is shown in the accompanying drawings, in which:

Figure 1 is a semi-diagrammatic sectional view of a starter having an axially adjustable arma-,- ture, in the position of rest,

is as follows:

' Figure 2 is a plan of connections of the starting device,

Figure 3 shows the starter in engagement, but

with the plate-clutch out of engagement, and

Figure 4 shows the starter in the working posi- 5 tion. i

In Figures 1, 3 and 4, I is the armature of an electric starting motor which in known manner can be axially displaced by the magnetic force of the field winding. On the armature shaft 2 is keyed a flywheel 3 and a pinion 4 is revolubly mounted on the shaft 2. The pinion 4 has a shank 5 which has an external thread 6 of quick pitch. A nut I can move on the shank by means of the thread 6. The torque of the armature I is transmitted to the pinion 4 through a plateclutch .8. The plates 9 of the clutch engage by means of-projections It) in recesses H in the flange i2 of the flywheel 3, whilst the plates l3 engage by projections in grooves IS in the nut I. A spring I1 is tensioned between the nut I and a stop IE on the shank 5 of the pinion, and the spring tends to push the nut I against the plates. 6

In an opening 20 of the casing ill a lever 19 is pivotally mounted above the plate-clutch 8. One end of the lever projects into the casing, and strikes against a flange 2| on the nut I. when the lever is rocked, and displaces this latter on the shank 5. The lever is pulled back by a spring 24 into its position of rest. Further, a switch 22 is so arranged on the casing I8 that the switch arm 25 is brought into the switched on position by a finger 23 on the lever I9 when the lever is rocked. The switch arm carries a contact 26, 5 opposite to which a contact 21 is fastened in an insulated manner on the casing. The switch arm 25 is held in its on position by a holding coil 28 and is raised by a spring 29 as soon as the holding'coil is deprived of current.

In the diagram of connections, Fig. 2, 30 is a battery, one pole of which is connected to earth and the other pole to a brush 34 of the starting armature I.- To the otherbrush 35 is connected one end of an auxiliary field winding 3| and one end of the holding coil 28 of the switch 22 as well as one end of the main field winding 33. The two other ends of the windings 28 and 3| are connected to one pole of the switch 32, the'other pole of which is earthed. The second end of the winding 33 is connected to the insulated contact 21 which lies opposite the contact 26 on the switch arm 25 connected to earth.

The mode of operation of the starting device In order to start the internal combustion engine, the switch 32 is closed, thus closing the circuit through the auxiliary field winding 3|. It is plain from Fig. 2 that the holding coil 23 in parallel with the auxiliary field winding is also excited by the closing of the switch 32, but as that coil is unable to close the switch 22 which controls the circuit through the main field winding of the motor, the closing of the switch 32 brings the auxiliary field winding only into operation. The result of this is, first, that the armature I is axially displaced in known manner by the magnetic force of the auxiliary field winding 3| and set in slow rotation. At this time the clutch is sufficiently engaged, that is, there is a sufficient frictional clutch connection between the armature I and the pinion 4, by way of the pressure of the nut I against the clutch plates under the tension 01' the spring I1 and the engagement between the nut and the shank of the pinion, to cause the pinion to partake of the slow rotation of the armature and to be carried along with it until the pinion engages in the of spring I! to continue in rotation, first screws itself along the shank of the pinion further toward the plates in consequence of the threaded connection between the nut and the shank of the pinion and their relative rotary movement and thereby puts the clutch into operation on the pinion.

The torque of the starting motor is however too small in this first switch position to turn over the engine and the motor stops. The lever I9 is now moved into the position shown in Fig. 3. On rocking the lever, the nut I is moved away from the clutch plates toward the stop I6 against the tension of the spring I! and thereby the clutch released. At the same time the switch arm 25 is pressed by the finger 23 against the contact 21. The working currentcircuit is thus now cut in, since the main field winding is also earthed through the switch 22. The starting motor now runs idly with the inertia mass at a high speed and a series wound motor attains of course a very high speed. In order to. 're-engage the clutch 8, the lever I9 is moved back into its starting position. The spring. I! again pushes the nut 1 toward the plates and thus initiates thedriving connection between the armature I and flywheel 3 on the one hand and the pinion 4 on the other.

The nut I now presses the plates together with a force which corresponds to the torque required on the pinion, or, what amounts to the same thing, in accordance with" the load imposed on the inertia. mass in turning over the engine. The working current circuit of the starting motor remains closed by the holding coil 29 so that the starting motor can further assist the action of the flywheel 3. When the speed of the starter on starting the engine is exceeded by the speed of the engine, the pinion comes out of engagement in known manner.

In the above-described mode of operating the starting device, it is to be noted that the succession of operations are the advancement of the pinion into engagement with the toothed rim of the flywheel by displacement of the armature upon closure of the switch 32 of the auxiliary.

winding, then disconnecting the pinion from the inertia mass and setting the latter into full speed rotation by movement of the lever I9 to throw out the clutch and close the switch 22 of the main field winding, and then reconnecting the pinion with the inertia mass, and that damage to the pinion and the toothed rim of the flywheel is avoided by reason of the fact that the pinion is advanced into engaging position while the armature and the connected inertia mass are in slow rotation due to the initial excitation of the auxiliary field winding only.

However, the pinion can also be put in engagement by the lever I9 instead of with the aid of the displaceable armature, the nut I and the shank of the pinion being so formed that the nut .can again screw itself back toward the clutch to a distance corresponding to the displacement for engaging the pinion, in order to make the clutch operative. This makes it possible to effect the engagement of the pinion with the toothed rim of the engine flywheel after the inertia mass has been set in and while it is still in full speed rotation and without damage to either the. pinion or the engine flywheel, for at the moment when the pinion is moved by the lever toward the engaging position of the pinion with the engine flywheel the clutch becomes disengaged and the connection between the pinion and the rapidly rotating inertia mass is thereby broken and remains so as long as the lever is pressed against the nut. After the pinion is thus engaged with the toothed rim of the engine flywheel, the lever I9 is moved back to its neutral position and this movement of the lever, of course, relieves the nut 'I from the pressure of the lever against it, whereupon the spring I'I again pushes the nut toward the clutch plates and thus initiates the driving connection between the rapidly rotating inertia mass and the pinion to turn over the engine through the established engagement of the pinion with the toothed rim of the engine flywheel.

It is further apparent that the last-described method of starting does not necessarily require the device to include the electric motor'shown therein or any electric motor at all, for any motor whether electric or not or even manual means suitable for bringing the inertia mass up to the required rotation speed may be employed. But in carrying out the last-described method of starting by the device with the electric motor and circuit arrangements shown in the drawings, the first operation step of setting the inertia mass in full speed rotation before the pinion is engaged with the engine flywheel may be performed by leaving the switch 32 for the auxiliary field winding of the motor open so as to avoid that displacement of the armature which would advance the pinion into engagement with the engine flywheel before the inertia mass has been speeded up, and manually closing the switch 22 for the main field winding as may be required to set the armature and the connected inertia mass into full speed rotation.

A further advantage of the starting device according to the invention consists in that the use of a separate free-wheel device for the idle high speed running of the starting motor is avoided.

I declare that what I claim is:

1. A starting device for internal combustion engines comprising an inertia mass, ashaft ropinion having a shank, a nut mounted to rotate on the shank of said pinion, a plate-clutch between said pinion. and said inertia mass controlled by said nut and means operable at will in all positionsof said pinion to displace said nut relatively to said pinion to disengage said clutch.

2. A starting device for internal combustion engines comprising an inertia mass, a shaft rotatably mounting said mass, means for setting said inertia mass in rotation at high speed, a

driven member mounted on said shaft, a friction clutch between said member and said inertia mass, an automatically operating pressure-member controlling said clutch and means manually operable to displace said pressure-member relative to said clutch in a manner to operate said clutch at will.

3. A starting device for internal combustion engines comprising a motor, a shaft rotatably mounted in operative relation to said motor to be driven thereby, a pinion freely mounted on said shaft for rotation and axial movement along said shaft into engagement with a member of the engine to be started, said pinion having a shank; a nut mounted to rotate on the shank of said pin- -ion, a driving. connection between said pinion and said shaft comprising a plate-clutch controlled by said nut and means operable at will with said shaft in rotation or at rest and in all positions of said pinion to displace said nut relative to said pinion to disengage said clutch.

4. A starting device for internal combustion engines comprising a motor, a shaft rotatably mounted in operative relation to said motor to be driven thereby, an inertia mass secured to said shaft, a pinion freely mounted on said shaft, a sleeve having an external thread secured to said pinion, a nut on said sleeve in engagement with said external thread, a plate-clutch connecting said pinionand said inertia mass and controlled by said nut, a spring urging said nut to engage said plate-clutch, and a lever operable at will to displace said nut in a direction disengaging said clutch.

5. A starting device for internal combustion engines comprising an inertia mass, means for setting said inertia mass in rotation at high speed, a rotatable element adapted to be driven by said inertia mass-and means for temporarily connecting said rotatable element wtih the engine for turning over the same, an automatically working multiple-part friction clutch establishing a driving connection between said inertia mass and said rotatable element, and means to prevent said working of saidclutch as said rotatable element is being connected with the engine and'as said inertia mass is being set in high speed rotation.

6. A starting device for internal combustion engines comprising the combination, with an engine gear adapted to be driven to turn over the engine, of a prime mover having arotatable shaft and operable atwill to set said shaft in highspeed rotation, a rotatable element normally out of enga ement with said engine gear but shiftable into said engagement to drive said gear, on automatically working multiple-part friction clutch establishing a driving connection between the shaft of said prime mover and said rotatable element, and means to prevent said working of said clutch as said rotatable element comes into contact with said engine gear upon operating said prime mover and shifting said rotatable element.

- '7. A starting device for internal combustion engines comprising the combination, with an engine gear adapted to be driven to turn over the engine, an inertia mass adapted to be set in high-speed rotation, a pinion normally out of engagement with said engine gear but shiftable into said engagement to drive said gear, an automatically workingmultiple-part friction clutch establishing a driving connection between said inertia mass and said pinion, and means operable at will to set said inertia mass in high speed rotation and shift said pinion into engagement with said engine gear, said means comprising an element operating on said clutch as said pinion is shifted to prevent said working of said clutch as said'pinion comes into contact with said engine gear.

8. A-starting device for internal combustion engines comprising the combination, with an engine gear adapted to be driven to turn over the engine, of an inertia mass adapted to be set in highspeed rotation, a pinion normally out of engagement with said engine gear but shiftable into said engagement to drive said gear, means comprising a multiple-part friction clutch and a pressure member automatically engaging said clutch to press its parts together for establishing a driving connection between said inertia mass and said pinion, and means operable at will to set said inertia mass in high-speed rotation and shift said pinion into engagement with said engine gear, said means comprising an element restraining said pressure member from engaging said clutch as said pinion comes into contact with said enmally out of engagement with said engine gear but shiftable into said engagement for the turning over of the engine, transmission-drive means between said inertia mass and said pinion comprising a multiple-part friction clutch automatically operating to complete the driving connection between said inertia means and said pinion for the rotation of the latter, means operable at will to set said inertia mass in low speed rotation, means automatically operating upon the setting of said inertia mass in low speed rotation-to shift said pinion into engagement with said engine gear, and means operable at will upon establishing said engagement to disengage said clutch and set said inertia mass in high-speed rotation.

10. A starting device for internal combustion engines comprising the combination, with an engine gear adapted to be driven to turn over the engine, of a rotatable shaft, a prime mover for rotating said shaft, a pinion mounted for rotation with said shaft and movement axially thereof into engagement with said engine. gear, said pinion having a shank extending therefrom along said shaft toward said prime mover, driving means between said shaft and said shank comprising a control member in threaded engagement wtih said shank, a multiple-part friction clutch and means yieldingly engaging said conof said clutch together, and means operable at will tb shift said control member along said shank to release said clutch. v

11. A starting device for internal combustion engines comprising a rotatable inertia mass,a rotatable member adapted to be driven by said inertia mass and normally out of engagement but movable axially into engagement with a part of the engine to turn over the latter, a clutch trol member with said clutch to engage the parts, 1

normally establishing a driving connection between said member and said inertia mass in all positions of said member but operable at will to break and remake the connection, means operable at will to drive said inertia mass at slow speed and at high speed, means automatically operating to move said member axially into engagement with said engine part when said memher is connected with said inertia mass and the latter is set in low driving speed, and means operable upon said clutch at will when said member is connected to said engine part to break the connection between said member and said inertia mass while retaining said member in connection with said engine part whereby said inertia mass may be set into high speed rotation while said member is disconnected therefrom but connected to said engine part and to restore said connection between said member and said inertia mass whereby the torque oi the high speed drive of said inertia mass may be transmitted through said member to said engine part 'to turn over the latter,

12. A starting device for internal combustion engines comprising a rotatable inertia mass, a rotatable member adapted to be driven by said inertia mass and normally out oi. engagement but movable axially into engagement with a part of the engine to turn over the latter, means comprising a clutch normally establishing a driving connection between said member and said inertia mass in all positions of said member for rotation of said member at substantially the speed of said inertia mass, means to run said inertia mass up to high speed while said member is in its normal position connected therewith and out of engagement with said engine part, and mechanical means operable upon said clutch and upon said member at will when said inertia mass is in high driving speed to first disconnect said member from said inertia mass and then axially move said member into engagement with said engine part and while said member is in said engagement with said engine part to restore said connection between said member and said inertia mass whereby the torque of the high speed rotation of said inertia mass may be transmitted through said member to said engine part to turn over the latter.

13. A starting device for internal combustion engines comprising a rotatable inertia mass, a rotatable engine-driving member adapted to be driven by said inertia mass and having a nonstarting position out of engagement with the engine but movable axially into said engagement to turn over the engine, means comprising a clutch normally establishing a driving connection between said engine-driving member and said inertia mass in all positions of said memberfor rotation of the latter at substantially the speed of said inertia mass, means to run said inertia mass up to high speed rotation with said engine-driving member in its said non-starting position, and a single manually operable member and associated means operable upon said clutch and said engine-driving member at will by operation of said manually operable member to disconnect said engine-driving member from said inertia mass while the latter is in highspeed rotation and axially move said enginedriving member into engagement with said engine and then to restore said connection between said engine-driving member and said inertia mass while retaining said engine-driving memher in engagement with said engine whereby the torque oi the high speed rotation of said inertia mass may be transmitted through said enginedriving member to said engine to turn over the latter.

ALBERT CALI-SEN. 

